Study On Hot Deformation Behavior,Microstructure And Properties Of TG6 Titanium Alloy

Titanium alloy has excellent properties and is an important raw material for the manufacture of aero-engine parts.TG6 titanium alloy can be used for a long time under high-temperature conditions of 600℃.In order to realize the tacit matching of microstructure and mechanical properties of TG6 titanium alloy,Firstly,the high-temperature flow behavior of TG6 titanium alloy at strain rates from 0.001 to 10s^-1and temperatures from 850-1050℃was systematically studied by Gleeble-3500thermal simulation compressor;secondly,the influence of heat treatment process on the microstructure and properties of TG6 titanium alloy was explored,and a heat treatment process system with excellent comprehensive properties was formulated.The main research process is as follows:Introduce correlation coefficient（R）and average relative error（AARE）to analyze the fitting accuracy of the model.It was revealed that different predictive capabilities of the high-temperature flow behavior of TG6 titanium alloy by all the four models（Arrhenius（AR）model,modified Johnson-Cook（MJC）model,modified Zerilli-Armstrong（MZA）model,Artificial Neural Network（ANN）model.AR model:R²was 97.376%and AARE was 14.16%;MJC model:R²was 97.42%and AARE was 18.5%;MZA model:R²was 90.598%and AARE was 19.32%;ANN model:R²was 99.94%and AARE was 2.14%）.On the other hand,based on the consideration of predictability and material parameters,MJC and AR models are the best choices for predicting the hot deformation behavior of TG6 titanium alloy.TG6 titanium alloy is highly sensitive to strain rate and deformation temperature.The stress is inversely proportional to the deformation temperature,and is proportional to the strain rate.In the stress-strain curve,the stress increases rapidly to the maximum value at the initial stage of strain,and then the stress begins to decrease slowly with the generation of dynamic softening.Since the dynamic softening and work hardening cancel each other,the stress-strain curve is finally in a balanced state.Through the characterization of microstructure,it is known that the softening mechanism of TG6 titanium alloy is two-phase region-dynamic recrystallize,single-phase region-dynamic recovery,in order to obtain good comprehensive properties of the alloy,the range of thermal deformation parameters can be considered as 850～950℃And the combination of 0.001～0.1 s^-1.During the heat treatment,the solution temperature has a significant effect on the composition and quantity of the phase,while the aging time mainly affects the phase morphology;second,the hardness at different solution temperatures is significantly different,the hardness value is the largest at 1050℃.The changes at different aging times are almost negligible;in addition,the tensile strength and plasticity are inversely proportional to the solution temperature,the best heat treatment process is the combination of 850℃/WC+48 h/AC.Since the solution has a great influence on the microstructure,the samples after different solutions were selected to test the corrosion resistance.The strength of corrosion resistance of TG6 titanium alloy mainly depends on the content and morphology of the phase.